Compressive stocking

ABSTRACT

959,627. Knitting. BURLINGTON INDUSTRIES Inc. Oct. 2, 1962 [Dec. 1, 1961, No. 37401/62. Heading D1K. Bare elastomeric polyurethane yarn is knitted into alternate courses of a compressive fabric with nylon body yarn of lighter weight than that forming the intervening courses, the polyurethane yarn being substantially embedded in the fabric. The polyurethane yarn which is non-foamed and may be mono- or multi-filament may be knitted circularly e.g. on a two or four feed machine. As shown the welt of stocking S is knitted at two feeders from two ends of 40 denier filament crimped or textured nylon yarn and the shadow welt 12 with two ends of 40 denier texturised yarn. When knitting the leg portion 14 the main feed supplies 40 denier raw nylon yarn (courses 22, 24, Fig. 2,) and the auxiliary station supplies 20 denier raw nylon yarn 26 and a bare 70 denier elastomeric polyurathane yarn 28 stretched approximately 225%. Alternatively, one feed may supply 50 denier raw nylon yarn while the other feed supplies either 30 denier raw nylon yarn and 70 denier polyurethane yarn or 20 denier raw nylon yarn and 140 denier polyurethane yarn. The ankle may be shaped by increasing the tension in the nylon yarn without altering the tension in the polyurethane yarn.

y 1963 A. BURLESON ETAL 3,098,369

COMPRESSIVE STOCKING Filed Dec. 1, 1961 INVENTORS %im)7511r/esan Mark N//0/)fle5 BY 61/154401, 644M United States Patent 3,098,369 COMPRESSIVESTOCKING Aaron Burleson and Mark Nicholas Holmes, Burlington,

N.C., assignors to Burlington Industries, Inc., Greensboro, N.C., acorporation of Delaware Filed Dec. 1, 1961, Ser. No. 156,459 4 Claims.(Cl. 66-178) This invention relates to knitted compressive or supportgarments, and in particular to circularly knit ladies con-n pressivestockings.

The invention involves circularly knit nylon fabric having bare,elastomeric polyurethane yarn knitted into alternate courses of thefabric, to provide strong and durable compressive garments exhibitingunique and desirable properties. The elastomeric polyurethane yarnsutilized are non-foamed, being generally single strand but composed ofeither multi-filament or monofilamen-t yarns which are commerciallyavailable for example from E. I. du Pont de Nernours and Company underthe names Fiber K and Lycra, from the US. Rubber Co. as Vy-rene, andfrom the Firestone Tire & Rubber Co. as Spandex.

A principal object of the present invention is the provision of noveltubular compressive fabrics and garments exhibiting superior two-waystretch, resulting from the incorporation therein of el-astomericpolyurethane yarn and the manner of its incorporation. Related objectsare the provision of sheer ladies compressive stockings, havingexcellent hand and feel.

A further object of the invention is the provision of compressivegarments adapted to be circularly knit at high speed, utilizing simpleand conventional circular knitting machines and procedures.Specifically, the garments are particularly suited for two-feed andfour-feed knitting.

Another object is to provide ladies compressive stockings having bare,elastomeric polyurethane yarn in corporated therein, in such manner thatthe elastomeric yarn does not detract from the appearance of thefinished stockings. Further objects will be in part evident and in partpointed out hereinafter.

The invention and the novel features thereof may best be made clear fromthe following description and the accompanying drawings, in which:

FIGURE 1 is a diagrammatic side view of a compressive stocking embodyingthe invention, and

FIGURE 2 is an enlarged diagrammatic view of the leg fabric of thestocking of FIGURE 1, showing the fabric in stretched and idealizedcondition for the sake of clarity.

In the drawings, the stocking S illustrated in FIGURE 1 includes theusual welt 10, shadow welt 12, leg portion 14, heel 16, foot portion 18and toe 20. The structure of the fabric may be readily understood from adetailed description of the knitting of the stock-ing.

By way of example, the stocking is knit on a conventional 400-needlecircular knitting machine provided with two feeds. Except possibly forthe heel 16 and toe 20, the entire stocking may be knit two-feed.Initially, the welt is knit with two ends of 40 denier filament crimpedor texturized nylon yarn, and the shadow welt 12 is then similarly knitwith two ends of 40 denier textur- -ized yarn. When the shadow welt iscompleted, the machine shifts into knitting of the body or leg portion14. For this purpose, the feed at the main knitting station is changedto 40 denier raw pirn nylon yarn, and the feed at the auxiliary knittingstation is changed to 20 denier filament raw pirn nylon yarn. A bare 70denier elastomeric polyurethane yarn is supplied at the auxiliaryknitting station with the 20 denier nylon yarn, and is knitted intherewith, The polyurethane yarn is tensioned and stretchedapproximately 225% as it is fed to the auxiliary knitting Patented July23, 1963 station of the machine, so that a relaxed length of about 12 to14 inches of polyurethane yarn, stretched to approximately 40 inches, isfed into each course along with 40 inches of nylon yarn.

The two-feed knitting above described proceeds through the leg portionuntil ankle tightening begins at the usual point. Ankle tightening maybe elfected by increasing the tension on the respective nylon bodyyarns, thereby decreasing the length fed per course and the size of theknitted loops. In accordance with the present invention, however, thetension of the polyurethane yarn is not altered, but remains constantthroughout the leg. This permits the use of a very simple feeding andtensioning device for the polyurethane yarn, which may be a feed wheelgeared directly to the machine drive to provide a uniform 12 inches ofrelaxed yarn per course, and since this feed remains constant throughoutthe stocking, a simple mechanical arrangement is permitted.

At the completion of the leg portion 14, the machine shifts into theheel 16 in conventional fashion, and at the completion of the heel, thefoot portion 18 may be knitted two-feed in the same manner as is the leg14. As in the leg, the relaxed length of polyurethane yarn fed percourse of the foot is uniform and the same as in the leg, wherebymachine design and operation is greatly simplified. At the completion ofthe foot, two-feed knitting may be terminated and the toe 20 knittedsingle-feed in conventional fashion. It will be recognized that the heel16 and toe 20 may be knitted either single-feed or twofeed, and may beknitted with a single yarn, or reinforced.

FIGURE 2 represents the leg and foot fabric, shown in stretched andidealized condition. As there shown, courses 22 and 2.4 are knit of thesame 40 denier raw pirn nylon yarn, and the alternate courses are knitthroughout of 20 denier raw pir-n nylon yarn 26 and the 70 denierpolyurethane yarn 28.

In the knitting above described, the nylon yarn is knit to the size of aconventional stocking, and the polyurethane yarn greatly extended, sothat on relaxation of the polyurethane yarn, the dimensions of thestocking are considerably less than those of a conventional stocking.The approximate shape of the stocking in as-knitted condition may be asillustrated in FIGURE 1 of the drawing, wherein the leg and footportions are substantially cylindrical. When the stocking is placed onthe log, it is necessarily stretched to conventional dimensions, and thecombination of yarns gives excellent fitting properties and compressivesupport. The compressive effect of the fabric is uniform and elfectivein the longitudinal as well as in the coursewise direction. In theas-knit condition, and also when the stocking is stretched on the leg,the polyurethane yarn is substantially embedded in the fabric, and theyarn exposed at the surface is predominantly nylon, whereby theappearance of the fabric approximates that of a nylon fabric. Whenstretched on the leg under wearing conditions, the density of each 40denier nylon yarn course approximates the density of the alternatecourses, including the 20 denier nylon yarn and the extended 70 denierpolyurethane yarn.

The stocking may be boarded and finished in the form illustrated inFIGURE 1, or if desired it may be boarded and finished in moreconventional form, wherein the upper section of the leg portion is Widerthan the ankle section thereof. The polyurethane yarn beingthermoplastic, the stocking is readily shaped in the usual boardingoperation. The stocking exhibits excellent dyeing and finishingcharacteristics.

The above example may be varied, in order to produce a slightly heavierfabric, by knitting through the leg portion with 50 denier raw pirn yarnat one feed, and with 30 denier raw pirn yarn and 70 denier polyurethaneyarn at the other feed. A similar stocking may be knitted on a340-needle circular knitting machine, supplying 20 denier raw pirn yarnwith 140 denier poly-urethane yarn to alternate courses, and 50 denierraw pirn yarn to the intervening courses. In some constructions,monofilament nylon yarn may be utilized, and thrown yarn containingtwist may be utilized in place of raw pirn yarn. It will be appreciatedthat various modifications may be made in the invention describedherein, without deviating from the scope and intent thereof as set forthin the appended claims.

We claim: 1. A knit compressive stocking knit throughout at least theleg portion thereof with nylon body yarn,

said portion having bare elastomeric polyurethane yarn knitted inalternate courses to give compressive support in the "longitudinal andcoursewise directions, said polyurethane yarn being embedded in thefabric so that the yarn exposed at the surface is predominantly nylon,the body yarn in the same courses with the polyurethane yarn beinglighter in weight than the body yarn in the intervening courses, wherebythe appearance of the fabric approximates that of a nylon fabric. 2. Aknit compressive stocking as set forth in claim 1 in which the relaxedlength of the polyurethane yarn knitted into alternate courses issubstantially constant throughout said leg portion.

3. A knit compressive garment knit throughout at least a portion thereofwith nylon body yarn,

said portion having bare elastomeric polyurethane yarn knitted inalternate courses to give compressive support in the longitudinal andcoursewise directions, said polyurethane yarn being embedded in thefabric so that the yarn exposed at the surface is predominantly nylon,the body yarn in the same courses with the polyurethane yarn beinglighter in weight than the body yarn in the intervening courses, wherebythe appearance of the fabric approximates that of a nylon fabric. 4. Aknit compressive garment as set forth in claim 3 in which saidpolyurethane yarn is knitted in every stitch of alternate coursestogether with the body yarn.

References Cited in the file of this patent UNITED STATES PATENTS2,396,166 Faucette Mar. 5, 1946 2,430,860 Cairns Nov. 18, 1947 2,949,023Holmes Aug. 16, 1960 2,962,885 Knohl Dec. 6, 1960 3,016,726 Lawson Ian.16, 1962

1. A KNIT COMPRESSIVE STOCKING KNIT THROUGHOUT AT LEAST THE LEG PORTIONTHEREOF WITH NYLON BODY YARN, SAID PORTION HAVING BARE ELASTOMERICPOLYURETHANE YARN KNITTED IN ALTERNATE COURSES TO GIVE COMPRESSIVESUPPORT IN THE LONGITUDINAL AND COURSEWISE DIRECTIOMS, SAID POLYURETHANEYARN BEING EMBEDDED IN THE FABRIC SO THAT THE YARN EXPOSED AT THESURFACE IS PREDOMINANTLY NYLON, THE BODY YARN IN THE SAME COURSES WITHTHE POLYURETHANE YARN BEING LIGHTER IN WEIGHT THAN THE BODY YARN IN THEINTERVENING COURSES, WHEREBY THE APPEARANCE OF THE FABRIC APPROXIMATESTHAT OF A NYLON FABRIC.